Controlling the delivery of threads during twisting



y 15, 1941- A. E. SUNDERLAND I 2,249,404

CONTROLLING THE DELIVERY OF THREADS DURING TWISTING Filed Jan. 19, 1939 gjrwe/wtom hatentea July 15, 19 41 UNITED STATES. PATENT OFFICE I CONTROLLING THE DELIVERY OF THREADS DURING TWISTING Alfred E. Sunderland, Asheville, N. 0., assignor to American Enka Corporation, Enka, N. 0., a corporation of Delaware 1939, Serial No. 251,820

3 Claims. (01. 5,7-59) This invention relates to improvements in the art of twistingthreads, and more particularly to those machines for the twisting of threads which are known in the art as upward twisters. Specifically, the inventionrelates to the control of the balloon adjustment in the use of machines of the type referred to, such adjustment depending upon the degree of twist and the denier of the thread being twisted, to thereby effect throughout a wide range of conditions a freer and more uniform delivery of thread from the supply bobbin than is possible with twisting machines at present in use.

The twisting machines known as upward twisters comprise revolving supply bobbins from which the untwisted threads are withdrawn for twisting, pigtail guides situated centrally above the supply bobbins through which the twisted threads are drawn, and take-up spools on which the twisted yarnor thread is wound, which spools are uniformly rotated by suitable means such as contact rollers at a selected constant peripheral speed. In twisting machines of this type now in use, each pigtail guide occupies a fixed position upon a guide bar located just above its respective supply bobbin, at a distance of approximately two inches, and no provision is made for altering this position, the guide bar to which the pigtails are attached being firmly aiiixed to the framework of the machine.

It has now been found that when 'twistin thread, particularly continuous multi-filament subjected momentarily to an increased tension due to the drag of the filaments over the surface of the bobbin, or to the plucking of the thread at the point where the filaments have become entangled. This increased tension upon the thread usually causes the filaments to become brokenor abnormally stretched, and the thus lengthened filaments to twist around the other filaments in such a way as to form what are technically known as loops and corkscrews in the twisted thread. The presence of such loops and corkscrewsrendersthe yarn unsuitable for certain textile purposes. As distinguished from the above the employment of large balloons having long axes may cause, the ballooning thread from one yarn package to become entangled with the thread from an adjacent yarn package undergoing twisting on the same machine, re-

sulting in entanglement or breakage of the thread and the interruption of operations incident thereto. It follows that the delivery of the thread is freer andmore uniform directly proportional to the increase in the radius of its rethread such as rayon on the type of' machine in question, in order to obtain a uniform yarn, free from defects, the-v thread should be delivered from the rotating supply bobbin as uniformly and freely as possible.

The centrifugal force set up by each pf'the rapidly rotating supply bobbins causes the thread to balloon betweenthe bobbin and the pigtail. guide, through which it is drawn, and]: have discovered that the freedom with which the thread leaves the supply bobbin is governed in a great measure by the angle which the ballooning thread makes with respect to the axis of the rotating bobbin. If the angle of the thread withrespect -to the axis ofthe bobbin is very acute, the inwhich are not liberated freely are broken, or arespective balloon. This reaches a critical point for the particular thread size with the resultant increase in the angle made by the thread with respect to the bobbin and the freer and more uniform delivery.

Of course, the angular position of the balloon-. ing thread with respect to the axis of its supply bobbin is dependent upon the size ofthe balloon and 'the size of the balloon varies with the. mass of the thread and the change in centrifugal force set up by the rotating bobbin. Inasmuch as in the rayon industry it is customary to utilize the same twisting machine to twist many diiferent weights of thread at different speeds, the

problem of controlling the size of the thread "balloon assumes major importance. For 'example, if two different yarns are run through the same twisting machine at the same bobbin speed, it will be found that the thread-which is heavier in weight will produce the larger balloon, while ,the lighter thread will yield a'smaller balloon,

and the thread will assume a more acute angle with respect to the bobbin.

Further, if it is desired to impart a high twist I to the thread, the supply bobbin must'be rotated at a high rate of speed in relation to the speed at which the thread is taken up on the receiving spool, whereas if a low twist is desired, the, supply bobbin must be-rotated at a lower rate of speed, and the size of the balloonvaries with the speed of rotation ofithesupply bobbin.

From the foregoing it will appear that in rated therein;

twisting machines now use, wherein the pigtail guide is in a fixed position, the size of theballoon and the angle of the thread to the rotating bobbin are correct for only one spool speed and one weight of thread. Thus if a'heavier or alighter weight thread were to be twisted with the guide being positioned the same distance from the bobbin, or if the same thread were twisted at a higher or lower bobbin speed, the size of the balloon and, therefore, the angle ofthread to the bobbin would depart from that which is preferred for the particular thread and best results would not be obtained.

1 It is an object of this invention to provide means which will effectively overcome the above mentioned disadvantages whereby the size of the thread balloon may be controlled to provide free and uniform delivery of the thread from the supply bobbin, regardless of the weight and denier Y of the thread'and the speed of rotation of the bobbin, the invention contemplating adjusting the distance of the pigtail guide from the supply bobbin to the position best suited to the weight and denier of the particular thread to be twisted and the speed of rotation of the bobbin.

Another object of the invention is'the provision of a method and means for controlling the ballooning of the thread during the process of twisting.

Another object of the invention is the provision of means for quickly adjusting the distance of the pigtail guidefrom the supply bobbin in the upward twist type of machine to the proper position for any weight of thread and any spool speed without stopping the machine with the resultant loss of time and energy incident thereto.

These and other objects will be more clearly understood from a study of the following description when taken in conjunction with the accompanying drawing, wherein:

Fig. 1 is a schematic front elevation of a porframe supports 2 (only one of which is shown) located at spaced points along its length. A

base plate 3 extends the length of the machine and has mounted thereon-spindles 4 each of.

which is adapted to receive thereon a spool '5 from which untwistedthread 8 is led upwardly through a pigtail guide 'I provided over each spintime during the process of twisting thread on a machine constructed in accordance with this invention, an experienced attendant, observing the.

ballooning thread, may quickly determine whether or not the balloon is of proper size to eifect the freest and most uniform delivery of the thread. By simply turning the crank 26, he may quickly and easily raise or lower guide bar 22 carrying pigtail guides 21 to the desired position, without in the least disturbing the twisting operation. The result is-that optimum conditions for twisting are assured, and an improved thread having uniform twist and tensile properties and substantially free from objectionable loops and cork screws is obtained.

Having now described my invention and the preferred embodiment of apparatus designed to carry it out, it is to be understood that various modifications may be made therein without departing from the spirit and scope of the invention. Therefore, it is my desire that my invention be limited only by the scope of the appended claims.

What I claim is:

1. ma twisting machine comprising a plurality of rotatable mountings for bobbins each containing a thread to be twisted and*a thread guide positioned axially of the mounting andspaced from the position assumed by the adjacent end of the bobbin when the machine is ready for a twisting operation, a device for controlling the degree of ballooning of the thread between the bobbins and the guides'comprising a bar extending longitudinally of the machine and supporting a plurality of said guides, revolvable means comprising .the support of said bar and means associated with said revolvable means for vertically adjusting said bar to fixed positions above the said bobbins.

2. A device for controlling the ballooning of the thread.in a machine for twisting textile threads wherein a plurality of threads are conducted upwardly from separate sources of supply to collecting devices through the intermediary of thread guides positioned axially above the said sources of supply, comprising a member adapted to support a plurality of said guides,-

means for supporting saidmember and means associated with said supportingmeans for verti- -cally adjusting said member to a fixed-position dle to thread guide 8 carried by traverse bar 9, and thence to collecting bobbins Ill driven by contact rollers ll mounted on shaft l2.

Afflxed to the end frame I and intermediate frames 2 by-means of bolts [3, l4 are brackets I! having arms l6 provided with lugsl1 and I 8 carrying worm wheels l9 therebetween, lugs I! being formed to accommodate screw shafts 20 which project upwardly into threaded blocks 2|, affixed to or made part of angle bar 22 extending the entire length of the machine and carrying part of the pigtail guides I.-

Screw shafts 20 are operated by engagement of worm wheels I! with worms 23 (see Fig. 3)

' afllxed to a shaft 24 which extends parallel to bar in a plane parallel to the axes of'said collecting devices and equidistant from the separate sources of supply.

3. In a twisting machine, a plurality of twisting bobbinsarranged longitudinally of the machine, a plurality of thread guides positioned ax ially above said bobbins, a common support in the form of a bar extending longitudinally of the machine upon which said guides are mounted, said bar being provided with threaded holes at spaced points along the length thereof,- and manu ally revolvable screw members adapted to engage said threaded holes, whereby said bar may be raised and lowered.

ALFRED E. SUNDEltLAND. 

